A HULL FOR A WATER CRAFT

The present invention relates to a hull for a water craft. More particularly but not exclusively it relates to a collapsible hull with flexible tension members.

An inflatable boat is a boat constructed with a hull surrounded by a tube for containing gas. The tubes aids in floatation and stiffness of the boat. For smaller boats, the floor and hull are often flexible, while for some longer boats, the floor typically consists of rigid floor fixed between side tubes. Often the transom is rigid, providing a location and structure for mounting an outboard motor.

The modern rigid inflatable boat (RIB) is a development of the inflatable boat, which has a solid hull and an inflatable tube surrounding. Some rigid inflatable boat have a vee shaped hull. The external vee shape of the hull may allow the hull to cut through waves more easily.

A thwart is a strut placed crosswise (port/starboard) in a ship or boat, to brace it beam-wise. Some inflatable boats have a thwart that can be folded and removed so the boat can be deflated or collapsed and rolled up for transport or storage.

It is an object of the present invention to provide a water craft hull that overcomes or at least partially ameliorates some of the abovementioned disadvantages or which at least provides the public with a useful choice.

STATEMENTS OF INVENTION

Accordingly, in a first aspect the present invention relates to a hull for a water craft, the hull comprising; a vee shaped inflatable body configured to be inflated comprising port and starboard sides and at least one flexible member extending therebetween, the flexible member being in tension when the body is inflated.

In one embodiment, the flexible member is of a size so as to be in tension when the body is inflated.

In one embodiment, the flexible member is a strap, cable or planar sheet.

In one embodiment, the flexible member cannot act in compression between the port and starboard sides.

In one embodiment, the flexible member acts as a thwart.

Preferable, the flexible member can only act in tension and not compression. In one embodiment, the flexible member is a strap.

In one embodiment, there are multiple straps spaced apart along the length of the body.

In one embodiment, there are three straps.

In one embodiment, the straps are over 40mm wide.

In one embodiment, the straps are 150mm wide.

In one embodiment, there is an inflatable tube extending from each of the port and starboard sides of the body.

In one embodiment, the body is relatively stiff when inflated.

In one embodiment, the body is composed of a dual layer material.

In one embodiment, the dual layer material is a drop stitch material.

In one embodiment, the dual layer material has a thickness between 20-100mm.

In one embodiment, the dual layer material has a thickness of at least 40mm.

In one embodiment, the dual layer material has a thickness of 65mm.

In one embodiment, the dual layer material comprises at least a HYPALON™ material.

In one embodiment, the body is formed of two flanks meeting together to form a, or part of a, keel; and extending away from each other, and terminating at upper surfaces (gunnels).

In one embodiment, the flanks form a depth between the uppers surfaces and where the flanks meet.

In one embodiment, the straps extend over the depth.

In one embodiment, the straps extend over the depth, between the gunnels.

In one embodiment, the straps span an internal width of the body.

In one embodiment, the straps span the beam width of the body. In one embodiment, the flanks resist substantial bending, bowing or buckling when inflated and in operation.

In one embodiment, the hull comprises rigid floor boards configured to be laid upon the straps, when the body is inflated.

In one embodiment, there are rigid floor boards laid upon the straps.

In one embodiment, the rigid flow boards act in compression, when the straps act in tension.

In one embodiment, the straps indirectly compress the floor boards.

In one embodiment, the vee shaped body has an aft section with a 4-5 degree vee shape.

In one embodiment, the vee shaped body has a bow section with a 15-17 degree bow shape.

In one embodiment, the beam width with the straps in tension is less than the beam width without the straps.

In one embodiment, the straps are elastic and provide tension inwards from the port and starboard sides, but do not stretch under operational conditions to a width greater than the beam width.

In one embodiment, the vee shaped body has two flanks extending away from each other that meet at a keel.

In one embodiment, the straps extend between the port and starboard sides to pull in the flanks of the vee shaped body towards each other.

In one embodiment, the vee shaped body flanks are always pushing outwards, or resisting the force of the strap.

In one embodiment, the hull comprises an inflatable tube or tubes attached or constrained to the port and starboard sides.

In one embodiment, the hull comprises a transom able to hold an outboard motor.

In one embodiment, the hull is configured to plane. In one embodiment, the port and starboard sides comprise upper edges called gunnels that the straps attach to.

In one embodiment, tension in the flexible member is caused by the body.

In one embodiment, tension in the flexible member increases as gas pressure in the body increases.

In one embodiment, tension in the flexible member is increased as vertical load on the body and/or keel increases during operation.

In one embodiment, the hull comprises supporting members intermediate the straps and the upper surfaces of the flanks and/or keel.

In one embodiment, the supporting members are composed of EVA foam.

Another aspect the invention relates to a water craft comprising the hull described above.

Another aspect the invention relates to a water craft comprising an inflatable concave shaped hull formed by flanks extending away from a keel, and a plurality of flexible members able to act in tension, but not in compression, extending intermediate opposing flanks, the craft further comprising inflatable tubes extending around a portion of the perimeter of the hull .

In one embodiment, the hull is vee shaped.

In one embodiment, each flank comprises gunnel at an upper edge.

In one embodiment, the flexible members are straps.

In one embodiment, the straps draw together the flanks.

In one embodiment, the straps attach to a region of the flank intermediate the keel and the gunnel.

In one embodiment, the flanks terminate at opposing gunnels

In one embodiment, the straps extend between the opposing gunnels.

In one embodiment, the straps draw together the opposing gunnels.

Another aspect the invention relates to a for a water craft, the hull comprising; a concave inflatable body formed of two outwardly extending flanks, the body having gunnels at its port and starboard edges of the flanks and at least one flexible member extending therebetween, the flexible member being in tension when the body is inflated.

In one embodiment, the hull is vee shaped.

In one embodiment, the flexible members are straps.

In one embodiment, the straps draw together the flanks.

In one embodiment, the straps attach to a region of the flank intermediate the keel and the gunnel.

In one embodiment, the flanks terminate at opposing gunnels

In one embodiment, the straps extend between the opposing gunnels.

In one embodiment, the straps extend about the gunnels to be attached at or towards outwales of the respective gunnels.

In one embodiment, the straps draw together the opposing gunnels.

Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the

accompanying drawings.

As used herein the term "and/or" means "and" or "or", or both.

As used herein "(s)" following a noun means the plural and/or singular forms of the noun.

The term "comprising" as used in this specification means "consisting at least in part of". When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner.

It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7).

The entire disclosures of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference. This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known

equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.)

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described by way of example only and with reference to the drawings in which :

Figure 1: shows a top perspective view of a hull of the present invention.

Figure 2A: shows a cross section through the longitudinal length view of a hull of the present invention.

Figure 2B: shows the forces apparent in a schematic view of a cross section through the longitudinal length of a hull

Figure 3: shows a side schematic view of a hull.

Figure 4: shows a cross sectional view of a hull strapped and unstrapped (shown in dashed lines).

Figure 5: shows a cross sectional view of a hull with floor panels and tubes attached Figure 6: shows a top perspective view of a hull with wider flexible members

Figure 7: shows a top perspective view of a hull with cables as flexible members Figure 8: shows a top perspective view of a hull with tubes attached, and a cut away view of the floorboard showing the flexible members

Figure 9A: shows a schematic cross section view of a dual layer drop stitch material to be used for the hull body.

Figure 9B: shows a schematic cross section view of a dual layer material to be used for the hull body.

Figure 9C: shows a schematic cross section view of a dual layer material to be used for the hull body.

Figure 10: shows a top perspective view of a hull with flexible members extending between the flanks.

Figure 11: shows a top perspective view of a hull with a round bottom. Figure 12A: shows a top perspective view of a hull with support members.

Figure 12B: shows a top perspective close up view of support members.

Figure 12C: shows a side view of a hull with support members.

DETAILED DESCRIPTION

With reference to the above drawings, in which similar features are generally indicated by similar numerals, a hull according to a first aspect of the invention is generally indicated by the numeral 1 and as shown in Figure 1. The hull 1 is to be used in a watercraft 100, as shown in Figure 8 The hull of the present invention has two main components comprising a body 2 and one or more flexible members 3. The body 2 forms a 'Vee' shaped hull as known in the art. Preferably the vee body is configured and shaped to plane on water. The body 2 is inflatable so as to be able to be deflated and packed down into a transportable state. An inflation and deflation point 14 will be located on the hull body 2, one location is shown in Figure 1. In the inflated condition, the body 2 is relatively stiff so as to form the shape of a Vee. The body 2 has the typical features of a hull, such as; flanks 4, gunnels 6 at the upper periphery of each flank 4, a keel 5 intermediate the two flanks 4, a bow 7, a stern 8, a stem 9, and a transom 10. In a deflated condition, the hull body 2 is able to be collapsed/deflated to be packed into a smaller footprint and/or volume. The deflated condition can be used for storage and/or transit.

In one embodiment the body 2 also comprises a one or more tubes 11 that run around the gunnels or upper periphery of the body 2 as shown in Figure 5. The tubes can be inflated to form an inflatable tubed boat as known in the art, and deflated like the hull body 2.

The hull 1 of the present invention also comprises one or more flexible members 3 that extend between the gunnels 6 on either flank 4 of the body 2, to act as thwarts in tension only (not in compression). The one or more flexible members 3 are configured to in operation, i.e. the body as inflated, be in tension as shown in Figure 2A and 2B. The flexible members 3 are able to collapse, and pack down, when the body 2 is deflated. The flexible members 3 do not prohibit collapse/deflation of the body 2, nor packing down or away.

Preferably the flexible members 3 are in tension during attachment. The flexible members 3 having a length between the gunnels 6 less than the inflated beam width of the body 2 without the flexible members 3 attached, as shown in Figure 4. As such, when the body 2 is inflated to its rigid or semi-rigid condition, the one or more flexible members 3 can deform the body 2 gunnels 6 towards each other so they are not able to separate as much as their unconstrained inflated configuration.

In an alternative embodiment, the body 2 is not deformed in from the gunnels, instead the one or more flexible members 3 are elasticated so as to always be in tension. However it likely that there will always be a degree of give in the hull body 2, so the gunnels 6 always draw together a little. There may be many ways in the art a skilled person is able to provide the one or more flexible members 3 to be in tension.

The purpose of the one or more flexible members 3 is to provide rigidity to the body 2. Typical boats of this nature often have a rigid hull, i.e. a rigid inflatable boat (RIB). These boats often have an inflatable tube as seen in the present invention, however their body or hull is rigid not inflatable. This is because the prior art technology is not able to provide a rigid enough hull that is both a vee shape and inflatable. The current invention has a vee shaped inflatable hull, which is typically only possible with a few known inflatable hulls - yet more rigidity is desired. To provide a more rigid inflatable vee shaped hull, the one or more flexible members 3 are used to draw the hull into a strained condition, increase it resistance to spreading between the gunnels 6, and/or increase its torsional strength.

The flanks 4 of the body 2 are suitably stiff so when inflated they resist crumpling, buckling or substantial bowing. During operational loads, such as the hull 1 travelling through a body of water, normal force loads X onto the keel 5 push the keel 5 upwards towards the flexible members 3 as shown in Figure 2B. This upwards force X wants to displace the keel 5 vertically towards the gunnel 6. This displacement wants to spread the gunnels 6 apart from one another, i.e. to open up the Vee. The one or more flexible members 3 resist this spreading apart of the gunnels 6 by acting in the tension in the tension direction Z. The spreading apart of the gunnels 6, is a particular feature of the shape of the hull 1.

The vee shape of the hull allows the water craft 100 to plane in operation. The planing of the watercraft 100 means that the majority of the displacement pressure (from the water) on the hull 1 is located at or towards the keel 5. This displacement pressure on the keel 5 has the effect of pushing apart the gunnels 6 from each other. Whereas displacement hulls have a water line towards the gunnels or towards the outer chines. This displacement pressure of the water wants to force the gunnels 6 towards each other

In a preferred embodiment the flexible members 3 are straps 3. There can be one or more straps 3 along the longitudinal length (aft to bow) of the hull 1. In one embodiment for example, on a hull less than 4 metres there are between three and four straps 3. In one embodiment for example, the straps are 150mm wide. However it is envisioned that a person skilled in the art will realise that the straps can depend on the characteristics of stiffness required or operational tension present, taking into account hull size, shape and material characteristics of the flexible members 3.

A skilled person in the art will realise that any substantially flexible material may be used to provide tension between the gunnels 6. The two requirements for the flexible members 3 are that they; are flexible, i.e. can be packed down for deflation of the hull 1; and the second requirement is that they are able to withstand tension between the gunnels 6, i.e. they are not significantly stretchable.

As such other flexible member 3, other such configurations such as cables 3A may also be used instead of, or in combination with, straps 3. The cables 3A may extend directly across the beam between gunnels 6. Alternatively, the cables may be laid diagonally between the gunnels 6. The cables may be criss-crossed along the length of the body 2. The cables 3A may be formed of a number of materials, such as fibreglass, carbon fibre, fabric, plastic, or metal. In other embodiments, instead of cables or straps the flexible members 3 may be a planar sheet. The sheet may cover the entire top surface between the starboard and port gunnels 6. The sheet is then able to take tension between the starboard and port gunnels 6. A further embodiment is shown in Figure 10 where flexible members 3 are affixed to, or integral with, the flanks 4 of the hull body 2. The flexible members 3 may be located at numerous positions on the flanks. However the flexible members 3 offer the most degree of hull rigidity when attached to the gunnels 6.

The applicant has found that using straps 3 less than 200mm wide appears to be optimum for a length of boat less than 4 metres.

Preferably the hull body is formed between a dual layer material. We had the area intermediate the 2 layers may have a compressed gas within it. Some examples of a dual layer material are a drop stitch material. The layers themselves may comprise a synthetic elastomer— such as chlorosulfonated polyethylene (CSPE) synthetic rubber (CSM) - also known as HYPALON™, polyurethane or PVC. Suitably stiff inflatable materials are known in the art for inflatable boats and stand-up paddle boards. A dual layer material is shown in Figure 9A however other substantially stiff yet inflatable materials are shown in 9B & 9C. Where Figure 9B shows an inflatable tube type system that extends between an inner surface 2A and an outer surface 2C. Wherein the inner material 2B is column. Figure 9C shows a foam type material 2B intermediate the inner surface 2A and the outer surface 2C. Figure 9A shows a HYPALON™ material 2A and inner surface 2A and outer surface 2C with the drop stitch material 2B interspersed there between.

The hull body 2, in particular the flanks 4, needs to be substantially stiff to transmit the loads upwards from the keel 5 or flanks 4 to the gunnels 6 without substantial bowing, crumpling or buckling of the flanks 4. The keel 5 may be stiffened further by a stiffening member 13 as shown in Figure 2A.

Supporting members 20 may be used intermediate the straps 3 and the upwards facing surfaces of the flanks 4 and/or keel. The supporting members 20 may be adhered to straps 3 by Velcro, adhesive means, sit snuggle in-between, or by other engagement means suitable. The supporting members 20 may be stitched or non-removably attached to the straps 3. Preferably the supporting members 20 are composed of EVA foam or other suitably rigid material. Ideally the supporting members 20 are able to be easily removed from the hull, so the they can be packed/compressed down into a transportable state.

The purpose of the supporting members 20 is to add additional resistance for the keel to prevent it from being pushed up, or from collapsing or bucking upwards towards the straps. The support members 20 act as spacers intermediate the straps 3 and the top surface of the keel. Preferably the support members are rigid enough to keep the spacing intermediate the straps 3 and the top surface of the keel, but are still able to be compressed so it they can be packed down into a transportable state, along with hull.

The support members may assist in the hull having rigid hull performance, but still be able to be packed down into a transportable state. Support members 20 may only be required in some boat configurations, where particularly large loads are induced on the hull. For example; with heavy or numerous crew, heavy sea conditions, and/or with higher horsepower engines.

In alternative embodiments the support members are inflatable. There may be one or more support members 20, i.e. under all straps, or under one or more straps. The support members 20 may be a number of different of shapes, and located at different areas between the flanks and straps, but preferably they are located between the keel (meeting point of the flanks) and straps.

In one embodiment, the EVA foam of the supporting members 20 can be any density, for example between 28kg/m3 to 420kg/m3. As long as the foam is able to compressed down into a compact form, and is able to support the straps. The higher density foams will support higher loadings however, i.e. rougher seas, faster planing etc. In one embodiment, a 3.8m boat, can be packed down in to a lm x 0.5m x 0.5m box, i.e. 0.5 of a cubic metre.

Any grade of foam hardness will likely be sufficient for hull stability, some example hardness characteristics are between 10 and 90 Asker C.

Floorboards 12 may be laid upon the straps 3, or gunnels, in between the starboard and port gunnels 6. Preferably the floorboards 12 lie intermediate the gunnels 6 and the tubes 11. In one embodiment, the tension of the straps 3 intermediate between the starboard gunnel 6 and port gunnel 6 puts the rigid floorboards 12 into compression. This is achieved by having the floorboards 12 'wedged' in between the gunnels 5 or tubes 11, or other like member at or towards each opposing gunnel 6, and the flexible members 3 drawing in opposing gunnels 6 towards each other so as to simultaneously squeeze the opposing edges of the floorboards together. The combination of the floorboards 12 in compression, and the straps 3 in tension, provide a substantially stiff upper assembly that will add rigidity and torsional strength to the hull 1. The floorboards 12 are as known in the art, for example in rigid inflatable boats. The floorboards may be one piece, or more preferably may be two or three pieces that can be laid inwards and easily removed during deflation of the hull 1.

As discussed previously preferably the inner surface 2A and outer surface 2C are of a HYPALON™ material. However other materials are envisaged by a person skilled in the art. The straps 3 or flexible members 3 may be integral or attached with the inner surface 2A or outer surface 2C. In one embodiment the straps 3 are integral with the outer surface 2C such that the straps extend around the perimeter, through an elongate cross section, of the hull body 2. However in a preferred embodiment, the straps 3 are separate straps that are attached to the hull body 2. In a preferred embodiment the ends of the straps are glued and/or mechanically attached to the gunnels 6. Preferably the straps extend over the gunnel and also the outwale 16. The straps are preferably glued and/or stitched to the hull body 2.

In a preferred embodiment the straps 3 comprise a HYPALON™ material. The straps 3 are preferably thin, fabric like, and not inflatable or stiff. The straps may be composed of numerous materials as known in the art that are not significantly stretchy, and are able to withstand tension, be flexible, and be durable and long lasting in a marine environment.

Where a vee shaped hull is mentioned and described, a similar concave shaped hull may also suffice. For example a 'U' shaped hull (Figure 11 shows an example of a round bottom/U shaped hull), double ended hull, deep or shallow or changing deadrise, multiple chine, hard or soft chine, etc. As long as the flanks, between the keel 5

(described herein as the bottom most part of the hull body 2, running between the bow and stern) and the gunnels 6, are suitably stiff to prevent buckling, and the flexible members 3 can extend across and above a portion of the hull body to draw the flanks 4 into each other to enhance rigidity, and prevent spreading of the gunnels 6 i.e.

shallowing of the hull body 2. Furthermore, the hull is preferably a planing hull so the displacement forces are located at or towards the keel 5 and not towards the gunnels 6. Where a round bottom or similar hull is described, or used, it is assumed it can be separated into two flanks 4, which are defined as being port and starboard of the hull body 2 midline, even though the flanks 4 are not well defined. The flanks may be integral with each other, or formed from different sections. Preferably the body 2, is one inflatable section.

Preferably the flexible members 3 are not deflected between their attachment points (at the gunnels or flanks). I.e. the flexible members 3 run straight, or un- interfered /unhindered, between their attachment points 15 / meeting points 15 with the body 2 on each flank 4.

Where gunnels 6 have been described, the gunnels 6 are in relation to location for the hull body, i.e. at the port and starboard upper and outermost edges of the flanks 4 of the body 2. Further additions to the hull, such as tubes located at a portion of the perimeter, may also be defined as gunnels in nautical terminology, but not in this specification.

Where in the foregoing description reference has been made to elements or integers having known equivalents, then such equivalents are included as if they were individually set forth.

Although the invention has been described by way of example and with reference to particular embodiments, it is to be understood that modifications and/or improvements may be made without departing from the scope or spirit of the invention.